This invention relates to improved heat exchange apparatus. In particular, it relates to tube-type heat transfer elements having turbulator devices for improved efficiency and maintenance.
This invention has utility in industrial and/or scientific applications involving heat transfer. A typical use occurs in the operation of refinery equipment, chemical plants and power plants. In such operations, large quantities of operating fluids, often at high temperatures need have heat removed. A presently used mode of heat removal involves the circulating of transfer or working fluid through a large number of tubes. The operating fluids are caused to flow by the working fluid tubes, permitting the exchange of heat between such fluids. Any event that reduces such heat exchange is deleterious to the process. While this example involves exchanging heat from an operating fluid to a cooling working fluid, it is unimportant to this invention the direction of heat exchange, i.e., from operating to working fluid, or vice versa. Of particular concern are [1] the forming of a contaminant layer on the inside tube wall, and [2] the forming of a thin annular, fluid film, sometimes described as a laminar film, of stagnant working fluid, just radially interior of the tube wall. Each of these disruptants apparently tends to reduce the exchange of heat between the adjacent fluids, acting as a heat insulator. Numerous approaches have been used to overcome these problems, such as the chemical and/or mechanical cleaning of the tube. A known system utilizes sponge rubber balls, flowing in a closed circulation system, to clean the tube interior. A brush cleaning system is described in the September, 1975 issue of Heating/Piping/Air Conditioning published by Water Services of America, Inc. The latter system includes cleaning brushes movable in a longitudinally extending tube. The direction of movement of the cleaning fluid may be reversed periodically so as to cause the brushes to traverse the length of the tube. The present system seeks to improve on the tube-cleaning systems described above. There are also different types of turbulators, using all the same basic principle--to mix slow moving fluid at the wall of the tube with the fast moving fluid in the center of the tube. Other heat exchange tube cleaners and/or turbulator devices are disclosed in U.S. Pat. Nos. 4,174,750, 4,412,558 and 4,412,583, incorporated herein by reference.
It is an object of the present invention to provide improved heat exchange elements and reversible fluid flow heat transfer equipment. In one aspect, a shell and tube heat exchanger or the like is provided with a plurality of smooth-walled straight tubes of circular cross section and fluid handling means for pumping fluid, such as cooling water, reversibly through the interior of the tubes in indirect heat exchange with a process fluid on the shell side of the exchanger. Improved heat transfer efficiency is achieved with a turbulator device adapted for mounting inside each of the heat exchange tubes for reversible flow service.